This application claims the priority benefit of Taiwan application serial no. 88120772, filed Nov. 29, 1999.
1. Field of Invention
The present invention generally relates to a method of controlling an ultraviolet (UV) glue size for liquid crystal display (LCD) devices, and more particularly to a method of controlling a UV glue size for an alignment table which is used in fabricating LCD devices.
2. Description of Related Art
In accordance with advances in electronic device techniques, the application of LCD devices is currently becoming wider. It is usually necessary to use glue materials for packaging LCD devices. This is usually done with a UV glue. As the LCD devices are scaled down, LCD device size is increasingly shrinking and the LCD circuit array is located closer to a substrate edge. Thus, the LCD panel design becomes even more critical. If the size of the UV glue is too large, the LCD packaging will be degraded and the LCD panel sawing will be more difficult. This leads to degradation of the LCD device performance and reduction of the yield of the LCD devices.
FIG. 1 is a schematic, cross-sectional diagram showing a conventional LCD device. As shown in FIG. 1, two glass substrates 2 and 3 are provided, wherein the substrate 2 can be a drive substrate and the substrate 3 can be an opposing substrate. Next, referring to FIG. 2A, a pixel matrix structure 4, a frame seal 5 and an externally connected pad 6 are provided on the substrate 2. An injecting hole 30 of the frame seal 5 is formed on one side of the pixel matrix structure 4. The pixel matrix structure 4 is composed of a pixel electrode, a storage capacitor, a switching element, etc. While packaging a LCD device, the frame seal 5 is sealed along the periphery of the pixel matrix structure 4 on the drive substrate 2. The drive substrate 2 can be sealed (overlapped) with the opposing substrate 3, wherein the drive substrate 2 must be precisely aligned with the opposing substrate 3, using alignment marks 7 and 8. The alignment mark 7 is formed on the drive substrate 2. The alignment mark 8 is formed on the opposing substrate 3 (shown in FIG. 2B).
FIG. 2B (corresponding to FIG. 2A) is a schematic, cross-sectional diagram showing an alignment step for conventional LCD devices. As shown in FIG. 2B, a glass substrate 2 is located on an alignment table 10, for example an X-Y-xcex8 alignment table. An alignment mark 7 is formed on the glass substrate 2. Another glass substrate 3 is located above the glass substrate 2 and an alignment mark 8 is formed thereon. A microscope 11 is provided, which is located above the glass substrate 3. The microscope 11 can move freely over the glass substrate 3 for determining whether the alignment mark 7 is aligned with the alignment mark 8. The glass substrate 2 can be aligned with the glass substrate 3 by the alignment of the alignment mark 7 and the alignment mark 8.
When aligning the glass substrate 2 and the glass substrate 3, it is necessary to seal the glass substrate 2 and the glass substrate 3 together. The method of sealing the two glass substrates 2 and 3 includes first irradiating the packaging glue 9 (UV glue) with UV light to seal the two glass substrate 2 and 3, slightly. The UV glue 9 is formed in the corners of the two glass substrates 2 and 3, as shown in FIG. 2A. The frame seal 5 formed on the glass substrate 2 is then treated with a pressure process and a baking process. Thus, the glass substrate 2 and the glass substrate 3 can be sealed very tightly. Next, a LCD material is injected between the glass substrate 2 and the glass substrate 3 through the injecting hole 30 (shown in FIG. 2A).
When the LCD circuit array is located closer to the edge of LCD substrates and the LCD panel design is increasingly critical, the demand for the quality of UV glue also becomes more critical. If the UV glue is too large, the quality of the LCD packaging will be degraded and sawing the LCD panel will be more difficult. This will then lead to degradation of LCD device performance and reduction of the yield of the LCD devices.
Accordingly, the object of the present invention is to provide a method of controlling the size of UV glue used to seal an alignment table of an LCD device.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a method of controlling the size of a UV glue for liquid crystal display (LCD) devices.
The first embodiment of the present invention includes using a frame seal as a size-controlling material to control the size of the UV glue. The frame seal includes a thermally hardened epoxy resin, a thermally hardened epoxy resin/thermal phenoxy resin, an epoxy resin which is inarched with a silicon rubber, or a silicon rubber.
First, a pixel electrode matrix structure is formed on a substrate. A frame seal material is provided along the periphery of the pixel electrode matrix structure. A size-controlling material is then provided. The size-controlling material is harder than the UV glue. The size-controlling material is preferably a frame seal, a thermally hardened epoxy resin, a mixture of a thermally hardened epoxy resin and a thermal phenoxy resin, an epoxy resin which is inarched with a silicon rubber, or a silicon rubber. The size-controlling material is formed with a predetermined shape around a predetermined place in which a UV glue is to be formed, using the predetermined place as the center of the size-controlling material. For example, the predetermined shape of the size-controlling material includes a U-shape, an arch-shape, a line-shape and a L-shape. Generally speaking, the predetermined shape of the size-controlling material is not limited to the foregoing shapes. Any shape of size-controlling material that performs the function of limiting the out-diffusion region of the UV glue can be used.
The UV glue is then formed in the predetermined place, which is, for example, in the corners of the pixel electrode matrix structure. Next, an alignment step is performed on the substrate. A pressuring process and a baking process are performed on the UV glue. Thus, the size-controlling material can be used for controlling the size of the UV glue.
The second embodiment of the present invention includes using a patterned device layer as a size-controlling material to control the size of the UV glue. The patterned device layer includes a liquid crystal display layer, a thin film transistor (TFT), a storage capacitor and a color filter.
At first, a pixel electrode matrix structure is formed on a substrate. A patterned device layer and a size-controlling material are formed on the substrate, simultaneously. The size-controlling material is harder than the UV glue in order to limit the out-diffusion region of the UV glue. Since the patterned device layer and the size-controlling material are formed simultaneously on the substrate, the size-controlling material can be the same as the patterned device layer, such as a liquid crystal display layer, a TFT, a storage capacitor or a color filter.
The size-controlling material is formed with a predetermined shape around a predetermined place where a UV glue is to be formed, using the predetermined place as the center of the size-controlling material. The predetermined shape of the size-controlling material includes a U-shape, an arch-shape, a line-shape and a L-shape. Generally speaking, the predetermined shape of the size-controlling material is not limited to the foregoing shapes. Any shape of size-controlling material that performs the function of limiting the out-diffusion region of the UV glue can be used.
The UV glue is then formed in the predetermined place, which is preferably the corners of the pixel electrode matrix structure. Next, an alignment step is performed on the substrate. A pressuring process and a baking process are performed on the UV glue. Thus, the size-controlling material can be used to control the size of the UV glue.
The third embodiment of the present invention combines composite the features of the first and the second embodiments includes using both a patterned device layer and a frame seal as a size-controlling material to control the size of the UV glue.
First, a first part of the frame seal material is formed along the periphery of the pixel electrode matrix structure and a second part of the frame seal material is formed in the pixel electrode matrix structure. The patterned device layer is provided on a substrate. Thus, the composite size-controlling material includes the second part of the frame seal and the patterned device layer. The material of the frame seal includes a thermally hardened epoxy resin, a thermally hardened epoxy resin/thermal phenoxy resin, an epoxy resin which is inarched with a silicon rubber, and a silicon rubber. The material of the patterned device layer includes a liquid crystal display layer, a TFT, a storage capacitor or a color filter.
The composite size-controlling material is formed with a predetermined shape around a predetermined place in which a UV glue is to be formed, using the predetermined place as the center of the composite size-controlling material. The predetermined shape of the composite size-controlling material is preferably a U-shape around the predetermined place in which the point-shaped UV glue is to be formed, using the UV glue as the center of the size-controlling material. The composite size-controlling material includes a patterned device layer and a frame seal material, wherein the patterned device layer is L-shaped and the frame seal material is line-shaped. Alternatively, the patterned device layer is line-shaped and the frame seal material is L-shaped. The predetermined shape of the composite size-controlling material is preferably an L-shape around the predetermined place in which the point-shaped UV glue is to be formed, using the UV glue as the center of the size-controlling material, with the patterned device layer in a line-shape and the frame seal material also in a line-shape. Generally speaking, the predetermined shape of the size-controlling material is not limited to the foregoing shapes. Any shape of size-controlling material that performs the function of limiting the out-diffusion region of the UV glue material can be used.
The UV glue is then formed in the predetermined place, which is, for example, in the corners of the pixel electrode matrix structure. Next, an alignment step is performed on the substrate. A pressure process and a baking process are performed on the UV glue. Thus, the size-controlling material can be used for controlling the size of the UV glue.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.